Background:Previous studies have shown the efficacy of antidepressants in the treatment of chronic depression. We report the results of a long-term study comparing desipramine hydrochloride and placebo for maintenance therapy of remitted patients with chronic depression.

Methods:Outpatients who met DSM-III-R diagnostic criteria for "pure" dysthymia (n=51), dysthymia with current major depression ("double depression") (n=64), or chronic major depression (n=14) were treated on an open basis with desipramine. Full and partial remitters after 10 weeks entered a continuation phase of open treatment with desipramine for 16 weeks. Remitted patients then were randomized to continue desipramine treatment or tapered to placebo treatment for a maintenance phase of up to 2 years. Relapse rates and time to relapse during maintenance therapy were compared between the two treatment groups.

Results:Acute-phase treatment results did not differ significantly according to chronic depression subtype. Remission persisted with a high degree of stability during the continuation phase. Relapse rates during the maintenance phase were 52% for the placebo group and 11% for the active desipramine group (ϰ2=8.1, P=.004). Most placebo relapses occurred during the first 6 months of maintenance therapy. Active medication was significantly more effective than placebo in that subgroup entering the maintenance phase in full remission and in those patients who fulfilled criteria for a diagnosis of pure dysthymia or double depression on entry to the study.

Conclusion:Long-term maintenance treatment with desipramine appeared to be effective in the prevention or postponement of relapse of depression in patients who responded to desipramine during the acute and continuation phases.